As per a new model developed at U of T Scarborough, a well known fossil of an early primate shares more in common with modern lemurs on the basis of how its teeth erupted. Developed by PhD student Sergi López-Torres and Associate Professors Mary Silcox and Michael Schillaci, the model re-examined the interpretation of Darwinius. Darwinius is the best preserved fossil primate known to exist.

They observed the sequence in which adult teeth come in -- called dental eruption -- in primates and discovered that it had more in common with lemurs as compared to squirrel monkeys, the model species used by the researchers who found Darwinius.

López-Torres said, “Every species has a particular pattern by which their teeth come in and this allows us to estimate the age of fossils that died before their adult teeth could emerge”. López-Torres added that it seemed the pattern of dental eruption for Darwinius was more similar to that of lemurs as compared to that of monkeys.

Before observing Darwinius, López-Torres carried out a large study of 97 living and fossil primates to get a clearer picture of how different species are compared through patterns of dental development. He discovered that the three most primitive ancestors, the ancestor to lemurs and lorises, the ancestor to monkeys, apes, and tarsiers, and the ancestor to all primates, shared the similar eruption sequence with each other. Their pattern shared some similarities with the dental eruption sequence discovered in Darwinius.